People today use multiple digital devices which are interconnected by various kinds of LAN (Local Area Network) and PAN (Personal Area Network) technologies. UPnP™ (Universal Plug and Play) and DLNA® (Digital Living Network Alliance) are standards focusing on the media consumption within home LANs, and allow users to play for example media stored in their network accessed storage (NAS) on a TV set in their living room. Furthermore, people have multiple portable devices and gadgets that are getting connected by LAN and PAN technologies while walking on the streets. At the same time, a lot of services are available in the Internet, offered by service providers or even by the user's own home networks, accessible through WAN (Wide Area Network) technologies. Numerous video sharing sites are available on the Internet. Also, many Internet radio stations are available, and Podcast sites offer audio and video together with well-formed meta-data.
Although people have started to create their personal networks (PN) of multiple devices that are connected via LAN connectivity, and use various services throughout their PNs, there are still many issues to use WAN services on PN devices.
Service composition, which creates a target service which is composed by multiple small services, is currently, a hot topic in this field. There are a number of XML-based standards to formalize the specification of web services, their flow composition and execution. For example, WSDL (Web Services Description Language) is used to express web services and BPEL4WS (Business Process Execution Language for Web Services) is used to describe the composition flow. The considered media devices, however, have limited capabilities according to their target use cases, and hence do not support every service, protocol, or media type available in the Internet. They only support limited operations and media types defined in their specifications and can usually not easily be extended as PCs. Therefore, a user can only enjoy a limited set of services on a particular device. For example, a device which only supports MPEG-2 video format cannot play out video content offered by a service provider that only distributes video in H.264 format. In such a case, transcoding could be applied so that the device can play out the video anyway; however, the user requires the skills, tools, and computational power to do the transcoding, or an external service provider has to perform the operation. An example of such transcoding service is OMA STI (Standard Transcoding Interface). In this case, the device cannot access the video content from the service provider on the fly and transcoding must be applied before. Service composition may enable to create a service which is composed of the content service and transcoder service. However, service composition is not usually performed for specific set of devices; hence the composed service does not always suit for each and every device.
Moreover, a device can only communicate with those services that support the same protocol set as the device. For example, UPnP™ devices are designed to communicate with other devices that also support the UPnP™ protocol, but the UPnP™ devices usually cannot communicate using other protocols. In order to use UPnP™ devices together with devices and services that communicate with a different set of protocols, there needs to be a protocol gateway between the different protocol domains.
Such a protocol conversion and bridging functionality between Web services and UPnP™ devices are found in the prior art. For example, US20070083618 proposes a technique in which a home network device can provide a home network device service to an external device through web service without directly installing web service associated functions therein. US20050210155 proposes an information processing apparatus including an information apparatus compatible with the UPnP™ discovery and an information apparatus compatible with the Web based discovery. WO2007140981 proposes a proxy-bridge for connecting UPnP compliant devices with Bluetooth® compliant devices. However, the prior art only addresses a static and specific set of technologies and any of these do not provide a generic way to solve the gap between the requirements and characteristics of offered service and the access and capability information of target devices.